Method and apparatus for routing internet calls

ABSTRACT

A telecommunications network ( 10 ) includes a public switched telephone network ( 12 ) and an Internet data network ( 14 ). The Internet data network ( 14 ) includes an Internet routing element ( 24 ) and a line access switch ( 26 ). The Internet routing element ( 24 ) is coupled to end office switches ( 16 ) and local switches ( 18 ) of the public switched telephone network ( 12 ) by modem trunks ( 30 ). The modem trunks ( 30 ) provide the Internet routing element ( 24 ) with Internet calls re-routed from the public switched telephone network ( 12 ) to prevent the Internet calls from congesting trunks ( 22 ) of the public switched telephone network ( 12 ). The Internet calls are received at an ATM multiplexer ( 58 ) within the Internet routing element ( 24 ). The ATM multiplexer ( 58 ) includes a pool of modems ( 60 ) that converts the analog signal on the modem trunks ( 30 ) into digital data. The ATM multiplexer ( 58 ) includes an ATM cell adaptation unit ( 66 ) that converts the digital data into ATM cells for transmission to an Internet Service Provider ( 42 ) over an ATM network ( 48 ). The ATM multiplexer ( 58 ) generates addressing information for the ATM cells through interworkings with signaling protocols of Internet calls. The line access switch includes a similar ATM multiplexer ( 94 ) to re-route Internet calls prior to entering the public switched telephone network ( 12 ).

RELATED PATENT APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/014,862, filed on Apr. 4, 1996.

TECHNICAL FIELD OF THE INVENTION

The present invention relates in general to telecommunications signalprocessing and more particularly to a method and apparatus for routingInternet calls.

BACKGROUND OF THE INVENTION

As access demand on the Internet or with on-line services grows, aproportional increase in the stress on telecommunications equipmentoccurs to support the access demand. Subscribers typically access theInternet through one or more Internet Service Providers. Each InternetService Provider is generally accessed by subscribers using discretelocal telephone numbers that provide broad coverage into a publicswitched telephone network. Access to the Internet Service Provider istypically a free local call where the local exchange carrier receives norevenues for the telephone usage. Internet Service Providers terminatein end offices of the public switched telephone network usingconventional subscriber numbering plans. No control exists as toInternet subscriptions, local telephone number assignments for InternetService Providers, or locations of Internet Service Providers. Internettraffic between subscribers and Internet Service Providers is mainlyrouted through the existing public switched telephone network over thesame trunks that carry voice, facsimile, and data calls.

Traditional network engineering traffic guidelines do not take intoconsideration the longer than average hold times of Internet calls. Mosttelecommunications equipment were designed based on an average callholding time of three to five minutes. However, average call holdingtimes for Internet calls is significantly longer. Current estimates arethat Internet and similar services have raised the total average callholding time to over ten minutes. This is expected to increase as theInternet continues to grow. Current end office switches within thepublic switched telephone network are not configured to support extendedaccess to the Internet. The increased average call holding times ofInternet calls place a strain on the public switched telephone networkthat affects the quality of service provided to and expected by thelocal subscriber. The public switched telephone network is no longerable to provide effective universal services to its customers whilemeeting the growing Internet demands.

Increased average call holding times decrease the carrying capacity oftrunks and, because the calls are typically free, decrease toll callrevenue per trunk as a result of the increased content per call. Thoughadditional trunks may be installed to support the increase in callholding times, such additions increase trunk group costs and operatingexpenses. Congestion occurs within the public switched telephone networkas customers attempt and re-attempt their calls. Service quality suffersresulting in increased customer dissatisfaction and increased servicecosts. Expensive and complex switch reconfigurations would be needed inorder to relieve the congestion on the public switched telephone networkcaused by Internet calls. Therefore, it is desirable to reduce thecongestion in the public switched telephone network caused by the longholding times of Internet calls.

SUMMARY OF THE INVENTION

From the foregoing, it may be appreciated that a need has arisen for atechnique of avoiding congestion on a public switched telephone networkcaused by the long hold times of Internet calls. In accordance with thepresent invention, a method and apparatus of routing Internet calls areprovided that substantially eliminate or reduce disadvantages andproblems associated with conventional processing of Internet calls.

According to an embodiment of the present invention, there is providedan apparatus for routing Internet calls that includes a pool of modemsto convert the analog signals of Internet calls re-routed from a publicswitched telephone network into a digital data format. An ATM celladaptation unit converts the digital data format into ATM cells. Anetwork interface transports the ATM cells to an Internet ServiceProvider over an ATM network separate from the public switched telephonenetwork. The ATM cells for the Internet calls include addressinginformation generated by an ATM addressing unit in conjunction with thesignaling protocols of an SS-7 network for determining the appropriatedestination of the Internet calls.

The present invention provides various technical advantages overconventional Internet call processing. For example, one technicaladvantage is to re-route Internet calls off of the public switchedtelephone network. Another technical advantage is to avoid placingInternet calls onto the public switched telephone network. Yet anothertechnical advantage is to transport Internet calls in asynchronoustransfer mode cell format over an asynchronous transfer mode network toan Internet Service Provider. Other technical advantages are readilyapparent to one skilled in the art from the following figures,descriptions, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings, wherein likereference numerals represent like parts, in which:

FIG. 1 illustrates a block diagram of a telecommunications switchednetwork;

FIG. 2 illustrates a block diagram of an Internet call through thetelecommunications switched network;

FIG. 3 illustrates another view of the telecommunications switchednetwork;

FIGS. 4A-C illustrate call control procedures at different congestionpoints within the telecommunications switched network;

FIG. 5 illustrates a block diagram of an Internet routing element withinthe telecommunications network;

FIG. 6 illustrates a block diagram of an asynchronous transfer modemultiplexer of the Internet routing element;

FIG. 7 illustrates a block diagram of a line access switch within thetelecommunications network; and

FIG. 8 illustrates a process flow for processing a call through the lineaccess switch.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a block diagram of a telecommunications switched network 10.Telecommunications switched network 10 includes a local public switchedtelephone network 12 and an Internet data network 14. Public switchedtelephone network 12 includes a plurality of end offices 16, a pluralityof local tandem switches 18, and a plurality of tandem switches 20. Endoffices 16, local tandem switches 18, and tandem switches 20 areinterconnected by a plurality of trunks 22 in order to provide adequatemeans for transporting telecommunications information from anoriginating subscriber to a destination subscriber in communication withend offices 16. Internet data network 14 includes Internet routingelements 24 that perform switching functions for Internet Callsre-routed from public switched telephone network 12. Internet datanetwork 14 may also include line access switches 26 coupled to Internetrouting elements 24 and public switched telephone network 12. A signaltransfer point network 28 provides control, management, andadministrative functions for public switched telephone network 12 andInternet data network 14.

Conventional operation of public switched telephone network 12 providesfor routing of Internet calls through the same configuration of trunks22 used to route voice, facsimile, and data calls. In order to avoidinstalling additional trunks 22 to relieve trunk congestion withinpublic switched telephone network 12, avoid installing more cross-pointsto relieve concentrator congestion within end offices 16, and avoidreplacing existing equipment within public switched telephone network12, all necessary to handle the longer hold times caused by Internetcalls, Internet data network 14 provides a means to re-route Internetcalls and eliminate the effect Internet calls have on public switchedtelephone network 12. Internet calls may be re-routed onto modem trunks30 from either local tandem switches 18 or end offices 16. Internetcalls may also be re-routed away from public switched telephone network12 onto modem lines 32 by line access switches 26.

FIG. 2 shows how an Internet call is transferred from a local subscriber40 to an Internet Service Provider 42 within telecommunications switchednetwork 10 after entering public switched telephone network 12. Forunloading Internet calls from trunks 22 within public switched telephonenetwork 12 to Internet data network 14, signal transfer point network 28works with local tandem switches 18, end offices 16, and Internetrouting elements 24 to assign modem trunks 30 and determine thedestination for routing the Internet call based on signaling protocolsof an SS-7 network 44. Conventional processing and routing is performedwithin public switched telephone network 12 of Non-Internet calls.Public switched telephone network 12 may also process and route Internetcalls in the event of problems occurring within Internet data network14. End office 16 or local switch 18 accepts the Internet call androutes the Internet call to an appropriate Internet routing element 24.Internet routing element 24 terminates the analog signals received frompublic switched telephone network 12 and adapts the call intoasynchronous transfer mode cell format. The asynchronous transfer modecells are multiplexed for transmission across an asynchronous transfermode network 46 to the appropriate Internet Service Provider 42.

FIG. 3 is another view of a telecommunications switched network 110showing potential congestion points due to Internet traffic.Telecommunications switched network 110 is shown separated into a publicswitched telephone network 112 and Internet data network 114. Forconventional operation, calls originating from a telephone subscriber139 or a computer subscriber 140 and destined for an information serviceprovider 142 are routed through public switched telephone network 112.Public switched telephone network 112 includes local access switch 126,originating end office switch 116, a tandem switch network 120, andterminating end office switch 117, all under the control and supervisionof a signal transfer point 128. Since calls destined for informationservice provider 142 occupy available resources of public switchedtelephone network 112 due to the long call holding times, such as forInternet access, congestion points occur within public switchedtelephone network 112. Congestion occurs at the subscriber side atoriginating end office switch 116, congestion occurs in the trunknetwork at tandem switch network 120, and congestion occurs at theterminating end at terminating end office switch 117. The congestion onpublic switched telephone network 112 will exceed engineered switch andnetwork trunking arrangements, resulting in call denial. Datasubscribers and voice subscribers may experience no dialtone, slowdialtone, and all trunks busy signals due to the degradation in thenetwork quality.

In order to alleviate the congestion on public switched telephonenetwork 112, calls identified as originating from a subscriber 139 or140 and destined for an information service provider 142 are redirectedfrom public switched telephone network 112 onto Internet data network114. Internet data network 114 includes a data switch network 146 thatreceives line side redirection of data calls from local access switch126 to alleviate the subscriber side congestion and originating endoffice switch 116. Data switch network 146 also receives trunk sideredirection of calls from originating end office switch 116 through anInternet routing element 124 in order to alleviate trunk networkcongestion at tandem switch network 120. Data switch network 146 alsoreceives trunk side redirection of data calls from tandem switch network120 in order to alleviate congestion at terminating end office switch117 through an Internet routing element 124. Data switch network 146then appropriately routes data calls to information service provider142. Identification and redirection of data calls is performed by signaltransfer point 128 through an SS7 messaging protocol. Internet routingelements 124 are used for grooming and transport of data call trafficonto data switch network 146.

In order to relieve subscriber side congestion at originating end officeswitch 116, a call destined for information service provider 142 isidentified in order to successfully divert the data call away frompublic switch telephone network 112. The identification process isperformed by signal transfer point 128. During a normal call processingsequence, line access switch 126 converts the analog POTS signaloriginating from a subscriber 139 or 140 to a digital DS0 signal andforwards that signal to originating end office switch 116 to begin callprocessing. Call requests that cannot be locally connected generate anSS7 message that is forwarded to signal transfer point 128. The call iscompleted when an SS7 message arrives back from signal transfer point128 with instructions on routing. When signal transfer point 128determines that the call is being placed to information service provider142 during its digital analysis process on the called party address, itinitiates a coordinating sequences of messages that allows originatingend office switch 116 to disconnect the call, and free the matrix andfree the trunk resource between line access switch 126 and originatingend office switch 116. Signal transfer point 128 directs line accessswitch 126 to divert the call from originating end office switch 116trunk resources to another resource, such as a dedicated DS0/DS1 circuitor a modem from internal pool with an ATM connection, that bypassespublic switch telephone network 112. Data switch network 146 then crossconnects the resources between line access switch 126 and informationservice provider 142. Line access switch 126 continues to monitor thesubscriber drop throughout the call, as would be performed for any call.Upon detecting that the subscriber goes on-hook, line access switch 126informs originating end office switch 116 so that the subscriber linecan be once again made available for incoming and outgoing calls. Lineaccess switch 126 also informs signal transfer point 128 so that thededicated DS0/DS1 circuit or ATM modem connection can be torn down andmade available for other calls. If the line disconnect originates atinformation service provider 142, signal transfer point 128 notifiesoriginating end office switch 116 and line access switch 126 in order toupdate their call status. All control information exchanges betweensignal transfer point 128, line access switch 126, and originating endoffice switch 116, are accomplished using standard signaling messages(such as Q.931) over standard interfaces.

Though line side redirection alleviates congestion directly atoriginating end office switch 116 and indirectly at tandem switchnetwork 120 and terminating end office switch 117, trunk sideredirection is performed to directly eliminate trunk network congestionat tandem switch network 120 and terminating end office switch 117.Trunk side redirection is performed at originating end office switch 116to adjust congestion at tandem switch network 120 and trunk sideredirection is also performed at tandem switch network 120 to addresscongestion at terminating end office 117.

In order to successfully divert data calls from the trunk network ofpublic switched telephone network 112, signal transfer point 128identifies calls originating from subscriber 16 or 18 and destined forinformation service provider 142. During a normal call processingsequence, originating end office switch 116 detects an off-hookcondition at subscriber 16 or 18 and generates an SS7 message that isforwarded to signal transfer point 128 for call requests that cannot belocally connected. The call is completed when an SS7 message is returnedfrom signal transfer point 128 with instructions on routing. The call isended when originating end office switch 116 detects the calling endgoing on-hook and thus terminates the call. When signal transfer point128 determines that the call is being placed to information serviceprovider 142, it directs originating end office switch 116 to divert thecall to Internet routing element 124. Internet routing element 124places the call on a resource, such as a dedicated DS0/DS1 circuit or amodem from an internal pool with an ATM connection, that bypasses publicswitched telephone network 112. Data switch network 146 connects theresource between originating end office switch 116 and informationservice provider 142. Originating end office switch 116 continues tomonitor the subscriber drop throughout the call. Once it detects that asubscriber has gone on-hook, originating end office switch 116 signalssignal transfer point 128 through the SS7 network so that the call'sconnection can be torn down and the resources made available for othercalls. If the disconnect originates at information service provider 142,signal transfer point 128 detects the condition and notifies originatingend office switch 116 so that it can update its call status.

Signal transfer point 128 works similarly with tandem switch network 120to redirect data calls from public switched network 112 onto Internetdata network 114 in order to alleviate congestion at terminating endoffice switch 117.

Signal transfer point 128 determines where an Internet call is to beredirected by maintaining a call detail record of calls throughtelecommunications switched network 110. For example, subscribersidentified as heavy Internet subscribers by signal transfer point 128may be line side redirected at line access switch 126 so that they areremoved from public switched telephone network 112 at an earliestpossible point in order to avoid congestion. Those subscribersidentified as normal Internet subscribers by signal transfer point 128may be redirected off of public switched telephone network 112 at thetrunk side of originating end office switch 116. Those subscribersidentifies as low density Internet subscribers by signal transfer point128 may traverse through public switched telephone network 112 withredirection not occurring until somewhere within tandem switch network120. In this manner, intelligent rerouting of data calls can occur toavoid congestion and provide smooth call routing within public switchedtelephone network 112.

Signal transfer point 128 may attempt to redirect the Internet call awayfrom public switched telephone network 112 at any and all of theredirection points discussed above. If a designated route to Internetdata network 114 is busy or not available, the Internet call overflowsfor routing back through public switched telephone network 112. Once theInternet call overflows back to public switched telephone network 112,the Internet call may be routed through alternate paths to Internet datanetwork 114 in higher level offices, once again achieving the goal ofremoving Internet traffic from the public switched telephone network112. The Internet call traverses through the entire public switchedtelephone network 112 only as a last resort in the event there are noother resources available to redirect the Internet call onto Internetdata network 114.

FIGS. 4A through 4C show the call control for redirecting Internet callsoff of public switched telephone network 112. FIG. 4A shows theredirection of a line side Internet call at line access switch 126. AnInternet call originates from subscriber 140 and proceeds through lineaccess switch 126 to originating end office switch 116. Originating endoffice switch 116 provides a dial tone for subscriber 140 and collectsthe digits entered by subscriber 140. Originating end office switch 116queries signal transfer point 128 through SS7 signaling. Signal transferpoint 128 receives the SS7 message at an SS7 interface 150 and performsa lookup of routing instructions within a signal control point 152 inconjunction with an administration unit 153. Signal control point 152returns a translated called number to originating office switch 116through SS7 interface 150. Originating end office switch 116 routes thecall based on the translated called number response. Originating endoffice switch 116 sets up an ISUP call between line access switch 126and a master controller 154 of signal transfer point 128. Mastercontroller 154 passes control and routing information for informationservice provider 142 to line access switch 126. Line access switch 126provides an interface to data switch network 146 and routes the Internetcall through data switch network 146 to information service provider142. Line access switch 126 issues a subscriber busy signal tooriginating end office switch 116 to indicate that subscriber 18 is offhook.

FIG. 4B shows redirection of a trunk side Internet call at originatingend office switch 116. An Internet call originates from subscriber 140to originating end office switch 116. Originating end office switch 116provides dial tone and collects digits entered by subscriber 140. Inresponse to the digits collected, originating end office switch 116queries signal transfer point 128 through an SS7 messaging protocol.Signal transfer point 128 receives the SS7 message at SS7 interface 150and obtains routing instructions from signal control point 152 inconjunction with administration unit 153. Signal control point 152returns a translated called number to originating end office switch 116through SS7 interface 150. Originating end office switch 116 sets up theroute for the Internet call based on this response. Originating endoffice switch 116 sets up an ISUP call between master controller 154 ofsignal transfer point 128 and an Internet routing element 144. Mastercontroller 154 passes control information to Internet routing element154. Internet routing element 154 establishes the connection for theInternet call onto data switch network 146 and provides the interfacewith data switch network 146.

FIG. 4C shows redirection of a trunk side Internet call at tandem switchnetwork 120. Subscriber 140 originates an Internet call throughoriginating end office switch 116 and to tandem switch network 120.Tandem switch network 120 queries signal transfer point 128 through theSS7 messaging protocol. The SS7 message received at SS7 interface 150and routing instructions are obtained from signal control point 152.Signal control point 152 returns a translated called number to tandemswitch network 120 through SS7 interface 150. Tandem switch network 120sets up an ISUP call between its associated Internet routing element 144and master controller 154 of signal transfer point 128. Mastercontroller 154 obtains routing information for information serviceprovider 142 from signal control point 152, in conjunction withadministration unit 153, and passes control and connection informationto Internet routing element 144. Internet routing element 144establishes the connection and provides the interface with data switchnetwork 146. The Internet call is then appropriately redirected throughdata switch network 146 to information service provider 142.

FIG. 5 is a block diagram of an Internet routing element 24. Internetrouting element 24 includes an administration subsystem 50, a matrixfabric subsystem 52, network terminators 54, and a resource subsystem56. Administration subsystem 50 provides control, maintenance, testaccess, and timing functions for Internet routing element 24. Networkterminators 54 provide the signal interfaces to and fromtelecommunications switched network 10. Matrix fabric subsystem 52provides the switching and cross-connect functions for Internet routingelement 24. Resource subsystem 56 provides subrate data multiplexing,multi-point junction, digital matrix bridge, and ATM multiplexingfunctions. Routing and transportation of Internet calls is performedthrough ATM multiplexer 58.

FIG. 6 is a block diagram of ATM multiplexer 58. ATM multiplexer 58includes a pool of modems 60, a control processor 62, an ATM addressingunit 64, an ATM cell adaptation unit 66, a backplane interface 67, and anetwork interface 68. In operation, an Internet call is routed to ATMmultiplexer 58 over a backplane 70 of Internet routing element 24. TheInternet call is processed by the appropriately assigned modem 60 inorder to convert from analog format into digital format. The digitaldata generated by modem 60 is converted into ATM cells by ATM celladaptation unit 66. Addressing information is placed into the ATM cellsby ATM addressing unit 64 in response to the determination of thedestination by control processor 62. Control processor 62 communicateswith signal transfer point network 28 to obtain the destinationinformation from the signaling protocols of SS-7 network 44. Once theATM cells have been generated and contain the appropriate addressinginformation, the ATM cells are transported to and from ATM network 46 bynetwork interface 68 or by backplane interface 67 through networkterminators 54.

FIG. 7 is a block diagram of a line access switch 26 to re-routeInternet calls prior to entering public switched telephone network 12.Line access switch 26 includes a digital loop carrier central terminal80 and a digital loop carrier remote terminal 82. Remote terminal 82includes a channel bank assembly 84 to service wire line subscribers.Remote terminal 82 also includes a fiber bank assembly 86 to providefiber optic connection services to subscribers through optical networkunits 88. A common control assembly 89 provides control and interfacefunctions with central terminal 80 for channel bank assembly 84 andfiber bank assembly 86. Central terminal 80 includes a common controlassembly 90 to provide control and interface functions with signaltransfer point network 28 and remote terminal 82. Common controlassembly 90 also interfaces with channel bank assemblies 92 and ATMmultiplexer 94. Channel bank assemblies 92 provide communication to andfrom end office switch 16 of public switched telephone network 12. ATMmultiplexer 94 provides the access for Internet calls to Interfacerouting element 24 and has a similar structure to that of ATM interface58.

FIG. 8 shows the process flow of calls through line access switch 26. Atprocess step 100, a subscriber initiates a call that is routed throughremote terminal 82 and central terminal 80 to end office switch 16. Endoffice switch 16 determines at process step 102 whether the call is atrunk call for public switched telephone network 12. If not, end officeswitch 16 performs local call processing at process step 103. If thecall is a trunk call, signal transfer point network 28 determines atprocess step 104 whether the call is an Internet call. If not, endoffice switch 16 performs normal call processing over public switchedtelephone network 12 at process step 103. If the call is an Internetcall, signal transfer point network 28 determines at process step 106whether an Internet route is available for the Internet call. If not,end office switch 16 performs normal call processing of the Internetcall over public switched telephone network 12 at process step 103.

If the subscriber is making an Internet call and an Internet route isavailable, the pool of modems within ATM multiplexer 94 is appropriatelyconfigured and addressing information for the ATM cells is generated atprocess step 108. ATM multiplexer 94 determines at process step 110whether the pool of modems was successfully configured to handle theInternet call. If not, then process flow proceeds back to process step106 to determine if a different Internet route is available to handlethe Internet call. If the pool of modems was properly configured tohandle the Internet call, central terminal 80 of line access switch 26connects the subscriber to the appropriate modem at process step 112.Central terminal 80 disconnects the Internet call from end office switch16 such that the Internet call now will not be processed over publicswitched telephone network 12.

Central terminal 80 determines at process step 114 whether thesubscriber was successfully connected to the appropriate modem. If not,then process flow proceeds back to process step 106 to determine if adifferent Internet route is available to handle the Internet call. Ifsubscriber to modem connection was successful, ATM multiplexer 94 beginsgenerating and transporting ATM cells to ATM network 46 either directlyor through backplane interface 67 and network interface 68 of Internetrouting element 24. Central terminal 80 associates a do not disturbservice with the subscriber at process step 116 and informs end officeswitch 16 of this condition. Central terminal 80 monitors the Internetcall for disconnection by the subscriber at process step 118 andappropriately terminates the do not disturb service upon completion ofthe call.

In summary, an Internet calls are routed away from the public switchedtelephone network in order to avoid congestion caused by the longer thanaverage hold times of Internet calls. Internet calls are routed to anInternet data network that includes an Internet routing element and aline access switch. The Internet routing element and the line accessswitch employ ATM multiplexers that connect the Internet calls to a poolof modems and convert the digital data generated by the modems into ATMcells for transmission to Internet Service Providers over an ATMnetwork. The ATM multiplexers work with a signal transfer point networkand an SS-7 network to generate the addressing information for the ATMcells.

Thus, it is apparent that there has been provided, in accordance withthe present invention, a method and apparatus for routing Internet callsthat satisfy the advantages set forth above. Although the presentinvention has been described in detail, it should be understood thatvarious changes, substitutions, and alterations can be made herein. Forexample, though the present invention has been described with referenceto Internet calls, other types of calls with longer than average holdingtimes may be routed in a similar manner. Other examples are readilyascertainable by one skilled in the art and may be made withoutdeparting from the spirit and scope of the present invention.

What is claimed is:
 1. A telecommunications network, comprising: a lineaccess switch operable to transfer telecommunications signals for callsto and from a subscriber; an originating end office switch operable totransfer telecommunications signals for calls routed to and from theline access switch; a tandem switch network operable to transfertelecommunications signals for calls routed to and from the originatingend office switch; a terminating end office switch operable to transfertelecommunications signals for calls routed to and from the tandemswitch network, the terminating end office switch operable to transfertelecommunications signals for calls routed to and from an informationservice provider; a data network operable to transfer telecommunicationssignals for a call between the subscriber and the information serviceprovider, the data network receiving the call originating from thesubscriber and destined for the information service provider asredirected by any one of the line access switch, the originating endoffice switch, and the tandem switch network; a signal transfer pointoperable to supervise call routing at the line access switch, theoriginating end office switch, the terminating end office switch, andthe tandem switch network, the signal transfer point operable toidentify the call originating from the subscriber and destined for theinformation service provider, the signal transfer point operable toprovide call routing instructions to any one of the line access switch,the originating end office switch, and the tandem switch network toredirect the call over the data network identified as originating fromthe subscriber and destined for the information service provider thesignal transfer point operable to determine which one of the line accessswitch, the originating end office switch, the tandem switch network thecall is to be directed from in response to parameters associated withthe subscriber.
 2. The telecommunications network of claim 1, whereinthe line access switch directs the call originating from the subscriberand destined for the information service provider to the originating endoffice switch in response to call routing instructions from the signaltransfer point upon determination of congestion in a communication linkbetween the line access switch and the data network.
 3. Thetelecommunications network of claim 1, wherein the originating endoffice switch directs the call originating from the subscriber anddestined for the information service provider to the tandem switchnetwork in response to call routing instructions from the signaltransfer point in an event of congestion in a communications linkbetween the originating end office switch and the data network.
 4. Thetelecommunications network of claim 1, wherein the tandem switch networkdirects the call originating from the subscriber and destined for theinformation service provider to the terminating end office switch inresponse to call routing instructions from the signal transfer point inan event of congestion on a communication link between the tandem switchnetwork and the data network.
 5. The telecommunications network of claim1, wherein the signal transfer point uses SS7 messaging to identify andredirect the call originating from the subscriber and destined for theinformation service provider.
 6. The telecommunications network of claim1, wherein the data network receives the call originating at thesubscriber and destined for the information service provider from any ofthe line access switch, the originating end office switch, and thetandem switch network in an asynchronous transfer mode cell format, thedata network transferring the call to the information service providerin the asynchronous transfer mode cell format.
 7. The telecommunicationsnetwork of claim 1, wherein the parameters associated with thesubscriber include a number of calls destined for the informationservice provider originating from the subscriber.
 8. A method of routingdata calls in a public switched telephone network, comprising steps of:receiving a call from a subscriber at a local line access switch;determining whether the call is destined for an information serviceprovider; redirecting the call from the local line access switch onto adata network and away from a public switched telephone network uponidentifying the call as being destined for the information serviceprovider and in response to parameters associated with the subscriber,the data network transferring the call to the information serviceprovider; determining whether a communication link is available betweenthe local line access switch and the data network; directing the callfrom the local line access switch to an originating end office switch inthe public switched telephone network when the communication linkbetween the local line access switch and the data network is notavailable.
 9. The method of claim 8, further comprising steps of:receiving the call from the local line access switch at an originatingend office switch; determining whether the call is destined for theinformation service provider; redirecting the call from the originatingend office switch to the data network and off of the public switchedtelephone network upon identifying the call as being destined for theinformation service provider and in response to parameters associatedwith the subscriber.
 10. The method of claim 9, further comprising stepsof: determining whether a communication link is available between theoriginating end office switch and the data network; directing the callfrom the originating end office switch to a tandem switch network in thepublic switched telephone network when the communication link betweenthe originating end office switch and the data network is not available.11. The method of claim 9, further comprising steps of: receiving thecall from the originating end office switch at the tandem switchnetwork; determining whether the call is destined for the informationservice provider; redirecting the call from the tandem switch network tothe data network and off of the public switched telephone network uponidentifying the call as being destined for the information serviceprovider and in response to parameters associated with the subscriber.12. The method of claim 11, further comprising steps of: determiningwhether a communication link is available between the tandem switchnetwork and the data network; directing the call from the tandem switchnetwork to a terminating end office switch in the public switchedtelephone network when the communication link between the tandem switchnetwork and the data network is not available, the terminating endoffice switch providing communication service to and from theinformation service provider.
 13. The method of claim 11, furthercomprising steps of: receiving the call from the tandem switch networkat the terminating end office switch; directing the call to theinformation service provider, the call being routed from the subscriberto the information service provider over the public switched telephonenetwork when congestion exists, resources are unavailable, or inresponse to parameters associated with the subscriber in redirecting thecall to the data network.
 14. A method of redirecting data calls at aline access switch, comprising steps of: receiving a data call from asubscriber; providing a through path for the data call to an originatingend office switch; receiving routing instruction for the data call;establishing a redirect path for the data call to bypass the originatingend office switch in response to the routing instructions and parametersassociated with the subscriber; placing the data call onto the redirectpath; providing the originating end office switch with a do not disturbmessage to indicate that the subscriber is not available for anothercall.